Si4464/63/61/60
5.3.1.1. EZ Frequency Programming
In applications that utilize multiple frequencies or channels, it may not be desirable to write four API registers each
time a frequency change is required. EZ frequency programming is provided so that only a single register write
(channel number) is required to change frequency. A base frequency is first set by first programming the integer
and fractional components of the synthesizer. This base frequency will correspond to channel 0. Next, a channel
step size is programmed into the FREQ_CONTROL_CHANNEL_STEP_SIZE_1
and
FREQ_CONTROL_CHANNEL_STEP_SIZE_0 API registers. The resulting frequency will be:
RF Frequency = Base Frequency + Channel ? Stepsi ze
The second argument of the START_RX or START_TX is CHANNEL, which sets the channel number for EZ
frequency programming. For example, if the channel step size is set to 1 MHz, the base frequency is set to
900 MHz with the INTE and FRAC API registers, and a CHANNEL number of 5 is programmed during the
START_TX command, the resulting frequency will be 905 MHz. If no CHANNEL argument is written as part of the
START_RX/TX command, it will default to the previous value. The initial value of CHANNEL is 0; so, if no
CHANNEL value is written, it will result in the programmed base frequency.
5.3.1.2. Automatic RX Hopping and Hop Table
The transceiver supports an automatic hopping feature that can be fully configured through the API. This is
intended for RX hopping where the device has to hop from channel to channel and look for packets. Once the
device is put into the RX state, it automatically starts hopping through the hop table if the feature is enabled.
The hop table can hold up to 64 entries and is maintained in firmware. Each entry is a channel number; so, the hop
table can hold up to 64 channels. The number of entries in the table is set by RX HOP TABLE_SIZE API. The
specified channels correspond to the EZ frequency programming method for programming the frequency. The
receiver starts at the base channel and hops in sequence from the top of the hop table to the bottom. The table will
wrap around to the base channel once it reaches the end of the table. An entry of 0xFF in the table indicates that
the entry should be skipped. The device will hop to the next non 0xFF entry.
There are three conditions that can be used to determine whether to continue hopping or to stay on a particular
channel. These conditions are:
?? RSSI
threshold
?? Preamble timeout (invalid preamble pattern)
?? Sync word timeout (invalid or no sync word detected after preamble)
These conditions can be used individually, or they can be enabled all together by configuring the
RX_HOP_CONTROL API. However, the firmware will make a decision on whether or not to hop based on the first
condition that is met.
The RSSI that is monitored is the current RSSI value. This is compared to the threshold, and, if it is above the
threshold value, it will stay on the channel. If the RSSI is below the threshold, it will continue hopping. There is no
averaging of RSSI done during the automatic hopping from channel to channel. Since the preamble timeout and
the sync word timeout are features that require packet handling, the RSSI threshold is the only condition that can
be used if the user is in “direct” or “RAW” mode where packet handling features are not used.
Note that the RSSI threshold is not an absolute RSSI value; instead, it is a relative value and should be verified on
the bench to find an optimal threshold for the application.
The turnaround time from RX to RX on a different channel using this method is 115 μs. The time spent in receive
mode will be determined by the configuration of the hop conditions. Manual RX hopping will have the fastest
turn-around time but will require more overhead and management by the host MCU.
The following are example steps for using Auto Hop:
1. Set the base frequency (inte + frac) and channel step size.
2. Define the number of entries in the hop table (RX_HOP_TABLE_SIZE).
3. Write the channels to the hop table (RX_HOP_TABLE_ENTRY_n)
4. Configure the hop condition and enable auto hopping- RSSI, preamble, or sync (RX_HOP_CONTROL).
5. Set preamble and sync parameters if enabled.
Rev 1.2
33
相关PDF资料
SI4465ADY-T1-GE3 MOSFET P-CH 8V 13.7A 8SOIC
SI4466DY-T1-GE3 MOSFET N-CH 20V 9.5A 8-SOIC
SI4470EY-T1-GE3 MOSFET N-CH D-S 60V 8-SOIC
SI4472DY-T1-GE3 MOSFET N-CH D-S 150V 8-SOIC
SI4477DY-T1-GE3 MOSFET P-CH D-S 20V 8-SOIC
SI4483EDY-T1-GE3 MOSFET P-CH D-S 30V 8-SOIC
SI4484EY-T1-GE3 MOSFET N-CH 100V 8-SOIC
SI4488DY-T1-GE3 MOSFET N-CH 150V 8-SOIC
相关代理商/技术参数
SI4463-915-PDK 制造商:Silicon Laboratories Inc 功能描述:KIT DEV WIRELESS SI4463 915MHZ
Si4463-B0B-FM 功能描述:射频收发器 TRX ROM 63 EZRadioPRO RoHS:否 制造商:Atmel 频率范围:2322 MHz to 2527 MHz 最大数据速率:2000 Kbps 调制格式:OQPSK 输出功率:4 dBm 类型: 工作电源电压:1.8 V to 3.6 V 最大工作温度:+ 85 C 接口类型:SPI 封装 / 箱体:QFN-32 封装:Tray
Si4463-B0B-FMR 功能描述:射频收发器 TRX ROM 63 EZRadioPRO RoHS:否 制造商:Atmel 频率范围:2322 MHz to 2527 MHz 最大数据速率:2000 Kbps 调制格式:OQPSK 输出功率:4 dBm 类型: 工作电源电压:1.8 V to 3.6 V 最大工作温度:+ 85 C 接口类型:SPI 封装 / 箱体:QFN-32 封装:Tray
SI4463B1BFM 制造商:Silicon Laboratories Inc 功能描述:
Si4463-B1B-FM 功能描述:射频收发器 TRX RoHS:否 制造商:Atmel 频率范围:2322 MHz to 2527 MHz 最大数据速率:2000 Kbps 调制格式:OQPSK 输出功率:4 dBm 类型: 工作电源电压:1.8 V to 3.6 V 最大工作温度:+ 85 C 接口类型:SPI 封装 / 箱体:QFN-32 封装:Tray
Si4463-B1B-FMR 功能描述:射频收发器 TRX RoHS:否 制造商:Atmel 频率范围:2322 MHz to 2527 MHz 最大数据速率:2000 Kbps 调制格式:OQPSK 输出功率:4 dBm 类型: 工作电源电压:1.8 V to 3.6 V 最大工作温度:+ 85 C 接口类型:SPI 封装 / 箱体:QFN-32 封装:Tray
SI4463BDY 制造商:VISHAY 制造商全称:Vishay Siliconix 功能描述:P-Channel 2.5-V (G-S) MOSFET
SI4463BDY-E3 制造商:VISHAY 制造商全称:Vishay Siliconix 功能描述:P-Channel 2.5-V (G-S) MOSFET